(359) Vaccination Use among Pregnant Women 2016-2023: An Analysis Using Healthcare Claims

Background: Immunizing pregnant populations has increasingly been used to protect the mother, fetus, and infant from infectious diseases. Maternal antibodies serve as neonates’ primary source of protection during their first weeks of life when they are most vulnerable. Tdap and influenza vaccines have been recommended for pregnant women by the CDC since 2012 and 2010, respectively. COVID-19 vaccines became available in December 2020; however, vaccination was not recommended for pregnant women by the CDC until August 2021 despite well documented risks of severe respiratory infections during pregnancy.

Objectives: To describe demographic characteristics and Tdap, influenza and COVID-19 vaccination patterns of pregnant women using a U.S. database of healthcare claims.

Methods: Healthcare claims data of female patients aged 12-55 with a live birth between 01Jan2016 and 30Sep2023 were analyzed. Conception was derived as 273 days prior to the live birth claim. Vaccines were identified from 3 months before conception through the date of birth. Timing of vaccination was categorized as 1) pre-quarantine (01Jan2016-29Feb2020), 2) quarantine (01Mar2020-30Nov2020), 3) post COVID-19 vaccine availability (01Dec2020-31Jul2021), and 4) post COVID-19 vaccine CDC recommendation (01Aug2021-30Sep2023).

Results: A total of 6,679,413 birth events across 5,551,561 distinct patients were included. Mean age at first occurrence of live birth (index date) was similar across vaccination timing categories. The patient’s region at the live birth date was South (39.5%), Midwest (24.4%), Northeast (18.2%), and West (17.5%). Tdap vaccination occurred consistently in ~50% and influenza vaccination consistently in ~30% of patients across all categories until decreasing to ~24% post-COVID-19 CDC recommendation. COVID-19 vaccination occurred in 3.6% of patients during the post-COVID-19 vaccination availability category and 5.9% post COVID-19-vaccine CDC recommendation.

Conclusions: Despite CDC recommendations for Tdap and influenza, vaccination rates for pregnant women remained low, but were both consistent during each time period, with the exception of influenza rates decreasing post-COVID CDC recommendation. Overall Tdap rates are consistent with the U.S. general population vaccination rate, while influenza rates in pregnant women are approximately half. COVID-19 vaccination rates remain considerably lower than for Tdap or influenza and US vaccination rates. While the COVID-19 vaccination rates nearly doubled in the time period following the CDC’s recommendation, it is still unsatisfactorily low to adequately protect mothers and infants.